Tarek Anwar, Ashraf Mokhtar And Hanaa Zaghloul,

ABSTRACT
Statement Of The Problem: Bond Strength Is A Very Important Determinant Of Clinical Success Of Dental Prosthesis. However, With The Introduction Of Hybrid Ceramics, Further Information Is Needed Regarding The Use Of Universal Adhesives As Bonding Agents. Aim Of The Study: To Evaluate The Effect Of Surface Treatments And Universal Adhesives On The Micro-shear Bond Strength Of Hybrid Ceramics.

Materials and Methods: Two CAD/CAM Hybrid Ceramics (VITA Enamic (VE) And LAVA Ultimate (LU)) Were Used In This Study. Each Was Cut Into 4 Ceramic Specimens. The 8 Ceramic Specimens Were Divided Into 2 Groups (n=4) According To The Material. Each Group Was Subdivided Into 2 Subgroups (n=2) According To The Surface Treatment; Hydrofluoric Acid Etching (HF) And Sandblasting (SB). Each Subgroup Was Further Divided Into 2 Subgroups (n=1) According To The Universal Adhesive Used; Scotchbond Universal (SbU) And Futurabond U (FbU). Silane Was Applied On All Specimens For 60 Seconds. All Specimens Were Cemented With RelyX-Ultimate Resin Cement Through Microtubules. They Were Then Thermocycled As An Artificial Aging To Simulate The Oral Environment. Micro-shear Bond (?SBS) Test Was Performed On All Thermocycled Specimens Using The Universal Testing Machine.

Results: LU Showed A Higher Statistically Significant ?SBS Value Than VE (P<0.001). HF Showed A Better Statistically Significant ?SBS Value Than SB (P<0.001). No Statistical Significance Was Found Between The Two Tested Universal Adhesives (p=0.060).

Conclusions: 1) Ceramic Microstructure Had A Great Impact On The ?SBS. 2) HF Could Be Considered As A Reliable Surface Treatment Protocol Of Hybrid Ceramics. 3) The Presence Of MDP In The Universal Adhesive Did Not Have A Significant Influence On The Micro-shear Bond Strengths Measured.

AbdelFattah Elhabashy, Mohamed Z. Amer, Wael S. Ahmed And Wael M. Safwat,

ABSTRACT
Problem Statement: Stereolithographic Surgical Guides Were Introduced As An Aid To Overcome Blind Technique Associated With Flapless Implant Placement And To Compensate Surgeon Experience. This Study Was Conducted To Evaluate The Accuracy Of Flapless Placement Of Dental Implants In Posterior Mandible With And Without Using Stereolithographic Surgical Guide. Patient And Method: Twelve Patients, Ten Females And Two Males, Received Sixteen Dental Implants To Replace Missing Mandibular Posterior Teeth. All Patients Were Equally Divided Into Two Groups. In 1st Group, 6 Patients Received 8 Dental Implants Using Stereolithographic Surgical Guide Without Flap Reflection. While, In 2nd Group, 6 Patients Received 8 Dental Implants Using The Conventional Surgical Guide Without Flap Reflection. All Implants Were Subjected To Immediate Loading Within 1 Week. Preoperative And Postoperative CBCT Were Performed For Both Groups To Evaluate Accuracy Of The Actually Placed Implant In The Oral Cavity Compared With The Virtually Planned Implants In The Software. All Patients Were Clinically And Radiographically Assessed At Baseline (T0), After 6 Months (T1), And After 12 Months (T2) Of Follow Up Regarding To Implant Stability, Peri-implant Pocket Depth, Modified Sulcus Bleeding Index, And Marginal Bone Level. Result: All Implants Were Successfully Osseointegrated. There Were No Statistical Significant Differences Between Planned And Placed Implants In Both Groups Regarding To Angular Deviation, Horizontal Deviations At Coronal And Apical Parts, And Vertical Deviations At Coronal And Apical Parts (P= 0.645, 0.721, 0.442, 0.234, 0.328 Respectively). No Significant Differences Were Recorded Between Both Groups Regarding To Stability, (mSBI), And (PPD) At Different Time Intervals Of Follow Up Periods Either At, (T0), (T1), Or At (T2) (P=0.721, 0.798, 0.505 Respectively), (P=0.721, 0.105, 0.721 Respectively), And (P=0.505, 1.000, 1.000 Respectively). Nevertheless, There Were Statistical Significant Differences Between Both Groups Regarding To (MBL) Either At, (T0), (T1), Or At (T2) (P=0.010*, 0.001*, 0.001*respectively). Conclusion: Both Flapless Techniques Either Aided By Stereolithographic Guide Or Aided By Conventional Guide Give Comparable Good Results Without An Additional Superiority Regarding To Accuracy Parameters Of The Implant Inserted In The First Group By Stereolithographic Guide.

Hebat-Allah Mostafa Mohamed, Ahmed Mohamed Fayed , Dina Wafik Elkassas And Olfat Sayed Hassanien,

ABSTRACT
The Aim Of This Study Was To Evaluate The Color Stability Of Two Different In-office Bleaching Techniques With The Corresponding Post Bleaching Remineralizing Agent And Nano-hydroxyapatite Paste. Materials And Methods. Twenty-eight Patients Were Divided Into Two Groups (n=14), In Accordance With The Bleaching Agent Applied Either Photo Or Chemo Catalyzed Bleaching Agent (25% And 30% Hydrogen Peroxide), And In Accordance With The Remineralizing Agent Applied After Bleaching Either ACP (control Group) Or Nano-hydroxyapatite Paste. Color Stability Was Assessed Using A Spectrophotometer At Baseline, After Twenty-four Hours, After One Week, After Four Weeks And After 24 Weeks Time Intervals. The Results Were Submitted To Statistical Analysis Using Mann-Whiteny U Test And Friedman?s Test. Results. No Statistically Significant Difference Was Found Between Groups That Received ACP And Nano P In The Photo Catalyzed System, Meanwhile A Statistically Significant Difference Was Found With The Chemo Catalyzed Bleaching System After Nano P Application. Conclusion. Nano P Did Enhance The Color Lightening And Stability Of The Chemo Catalyzed Bleaching System.

Fayrouz Abdel Hassieb, Ashraf Hassan Mokhtar And Tamer Abd El Rehim Hamza,

ABSTRACT
Statement Of The Problem: Fracture Resistance Is Essential For The Long-term Success Of Endocrown Restorations. Recently The Use Of Hybrid Ceramics Had Been Used For Endocrown Fabrication Yet The Studies Comparing Their Fracture Resistance Are Limited. The Purpose Of This In Vitro Study: Was To Compare Fracture Resistance Of Recently Introduced Hybrid Ceramic And Lithium Disilicate Endocrown Restorations Cemented With Two Bonding Approaches.

Materials and Methods: Twenty Extracted Human Maxillary First Molars Were Divided Into Two Equal Groups Of Ten Teeth According To Ceramic Material Used Each Group: Group (E): Ten Teeth Were Prepared To Receive E-max Endocrowns. Group (V): Ten Teeth Were Prepared To Receive Vita-Enamic Endocrowns. Each Group Was Further Subdivided Into Two Groups (n=5) According To Bonding Approach: Sub Group (1) N=5: Endocrowns Cemented With Self-adhesive Rein Cement (Rely-X Unicem). Sub Group (2) N=5: Endocrowns Cemented With Self-etch Adhesive (Futurabond DC 8th Generation) And Self-adhesive Resin Cement (Rely-X Unicem). After Standardized Preparation Of All Samples Fracture Resistance Was Tested Using Universal Testing Machine.

Results: Showed That Ceramic Type Had A Statistically Significant Effect On Mean Fracture Resistance. Cementation Technique And The Interaction Between The Two Variables Had Non-statistically Significant Effect On Mean Fracture Resistance. Since The Interaction Between The Variables Is Non-statistically Significant, So The Variables Are Independent From Each Other.

Conclusions: 1) Lithium-disilicate Endocrowns Showed Higher Fracture Resistance Than Hybrid Ceramics Endocrowns. 2) Futurabond DC In Combination With Rely-X Unicem Increased The Fracture Resistance Of Hybrid Ceramic Endocrowns Approximating Their Performance To Lithium-disilicate Endocrowns.

Heba Talat Mustafa El-Wakeel, Mohamed Galal El-Behiery And Tarek Ibrahim El-Ghareab,

ABSTRACT
The Amount Of Hard Tissue Resorption Following Tooth Extraction Sometimes Jeopardizes Prosthetically Driven Implant Placement; Therefore, There Is Great Interest In Socket Preservation Techniques That May Result In Less Alveolar Bone Loss. For The Most Part, Research Has Focused On The Healing Of Alveolar Sockets And The Ramifications Of Post Extraction Implant Placement. The Alveolar Bone Crest Is Known To Lose Volume During The First 6 Months After Tooth Extraction, Mostly On The Buccal Wall. The Aim Of The Presented Study Is To Evaluate Clinically And Radiographically A New Alternative Technique For Socket Preservation By Placement Of Collagenated Cortico-cancellous Xenograft Over An Intact Buccal Plate After Extraction. Ten Patients Were Selected Who Need Extraction For Non-restorable Single Rooted Teeth Where Atraumatic Extraction Was Performed Using Periotome And Forceps And A Surgical Caliper Was Used To Measure The Buccolingual Dimension At A Midpoint Then A Periosteal Elevator Was Used To Carefully To Create A Pouch On The Buccal Aspect At Midpoint Areas Of The Socket. Prehydrated Collagenated Cortico-cancellous Xenograft, Composed Of 80% Granulated Mix & 20% Collagen Gel?,which Is In A Paste Form Presented In Syringe Was Next Placed In The Pouch Overlying The Buccal Plate With Its Syringe. Clinical And Radiographic Examination Was Done For Each Patient By A Cone Beam C.T (CBCT) At The Pre-determined Follow Up Periods: Immediate Postoperative (base Line) And Four Months Postoperatively. Either Using Cone Beam Or Caliber; There Was No Statistically Significant Change In Mean Bone Width Measurements After 4 Months.

Mai S. Elgohary, Hesham Abd El Megid Katamish And Maha A. Taymour,

ABSTRACT
Statement Of The Problem: Long-term Clinical Success Of Dental Restoration Is Influenced Not Only By Mechanical Property, Aesthetic Quality, And Biocompatibility, But Also By Marginal Accuracy. Large Marginal Gap Causes Failure Of A Crown By Dissolving Dental Cement So Plaque Can Easily Accumulate, Leading To Marginal Leakage And Secondary Caries. Factors Such As Type Of Finish Line Design And Thickness May Influence The Marginal Adaptation Of All Ceramic Crown Restoration.

Purpose: The Purpose Of This Study Was To Evaluate And Compare Marginal Accuracy In Anterior Single Crowns Having Different Finish Line Thicknesses Constructed From Two Types Of All-ceramic Restorations Made From Lithium Disilicate Glass Ceramic And Anterior Zirconia Using CAD/CAM Fabrication Technique.

Materials and Methods: Thirty-two Zirconia-based Bruxzir Anterior (Glidwell Dental Labs, Prismatik DentalCraft Inc. USA) And Lithium Disilicate Crowns IPS E.max CAD (IvoclarVivadent Gmbh, Burs, Austria), 16 Each, Were Fabricated With CAD/CAM Systems On A Specially Designed Stainless-steel Die To Ensure The Standardization Of Specimen Shape And Dimensions. The Marginal Accuracy For All Tested Crowns Was Evaluated By Using A Stereomicroscope (Nikon Eclips E600, Tokyo, Japan) Connected With An IBM Compatible Personal Computer Using A Fixed Magnification Of 45X., A Digital Image Analysis System (Image J 1.43U, National Institute Of Health, USA) Was Used To Measure And Qualitatively Evaluate The Gap Width. Then The Data Obtained Were Collected, Tabulated And Then Subjected To Statistical Analysis.

Results: Results Of This Study Showed That Finish Line Thickness Regardless To The Material Used Did Not Significantly Affect The Marginal Accuracy. And The Material Has Influence On Marginal Accuracy. A Value Of P < 0.05 Was Considered Statistically Significant, Two -way Analysis Of Variance Was Performed. Student T-test Was Done For Compared Pairs. Sample Size (n=8) Was Large Enough To Detect Large Effect Sizes For Main Effects And Pair-wise Comparisons, With The Satisfactory Level Of Power Set At 80% And A 95% Confidence Level.

Conclusions: More Conservative Preparation Of A Shallow Chamfer Has Similar Marginal Fit As Teeth With The Conventional Preparation For Both Ceramic Types Tested.

Mohammed El-Desoki Fouda, Ahmed Atef El-souda And Amany E. Badr ,

ABSTRACT

Objectives: The Purpose Of This Study Was To Evaluate And Compare The Shaping Characteristic Of Different Rotary NiTi Systems (Hyflex EDM One File, Reciproc R25, Wave One Primary) In Extracted Human Teeth Using Cone Beam Computed Tomography Scanning (CBCT). Methods: Fourty Five Mesiobuccal Canals Of Mandibular Molars With Angle Of Curvatures Between 25-45 Degrees, Were Randomly Divided Into 3 Experimental Groups (n = 15), According To The NiTi Rotary System Used, Hyflex EDM, Reciproc R25 And WaveOne. All Canals Were Instrumented Using The Three Systems According To The Manufacture Instruction, Scanned Before And After Instrumentation By Using CBCT Scanner To Evaluate Canal Transportation And Centering Ratio At 3, 6 And 9 Mm From The Apex. Data Were Statistically Analyzed And The Significance Level Was Set At P< .05.

Results: At 3 Mm From The Apex, Hyflex EDM Showed The Lowest Significant Canal Transportation Value And The Highest Centring Ability Compared With Reciproc R25 And WaveOne Systems. No Significant Difference In The Amount Of Transportation And Centering Ability Between Reciproc R25 And WaveOne Systems. At The Level Of 6 Mm From The Apex, Hyflex EDM Showed The Lowest Significant Value Of Canal Transportation And Highest Centring Ability When Compared With Other Systems, And Reciproc R25 Showed Significantly Less Canal Transportation And More Centering Ability When Compared With WaveOne. At The Level Of 9 Mm From The Apex There Were No Significant Difference In The Amout Of Transportation And Centering Ability Between The Three Groups. Conclusion: Hyflex EDM System Showed The Least Canal Transportation And The Highest Centering Ability Followed By Reciproc R25 System While WaveOne System Produced The Highest Transportation And Lowest Centering Ability.

Nouran A Mohamed, Rehab F Fathi And Houry M Baghdadi,

ABSTRACT
Aims And
Objectives: This Study Aims To Analyse Immunohistochemically The Expression Of Sonic Hedgehog (Shh) In Oral Epithelial Dysplasia (OED) And Oral Squamous Cell Carcinoma (OSCC). Methods: Fifty Formalin-fixed, Paraffin-embedded Specimens Of OED And OSCC, Twenty Diagnosed As OED And Thirty Diagnosed As OSCC, Were Included In The Present Study. Immunohistochemical Staining With Anti-Shh Primary Antibody Was Performed. Area Fraction Of Immunopositivity Was Estimated By Image Analysis Software.

Results: The Study Showed That Shh Signaling Molecules Are Highly Expressed In OED And OSCC. Conclusion: Over-expression Of Shh Is Found In OED And OSCC And Might Be Used As A Reliable Diagnostic Marker For Both Cases.

Ahmed Mohammed Salah, Mohammed Ezzat Elsayed, Sayed Mohammed Elmasry And Moataz Mostafa Bahgat Elmahdy,

ABSTRACT
The Purpose Of This Study Was To Evaluate The Effect Of Metal And Acetal Removable Partial Denture (RPD) Framework Materials On The Stresses Around Implant Supported Removable Partial Dentures. Material And Methods : The Study Was Carried Out On Mandibular Epoxy Class I Partially Edentulous Models With Two Parallel Implants Placed At Lower First Molar Area And According To Framework Materials, Two Groups Were Created: Group I : Acetal Partial Denture Framework, Group II: Metallic Partial Denture Framework, For Both Groups Acrylic Record Block With Metal Plate Was Made And Adjusted To Apply Occlusal Force On The Center Of The Metal Plates, Regarding The Models From The Right And Left Side, Stress Analysis Images Were Recorded For Both Groups At Stresses From 20 To 100 Newton, Using Photoelastic Machine And Means Of Stress Values Were Recorded For Both Groups, Tabulated And Statistically Analyzed.

Results: There Was A Difference In Means Of Stress Values Between Acetal And Metallic Partial Denture Frameworks Where Metallic Partial Denture Framework Showed Higher Stress Fringes Order Around Implant Compared To Acetal Denture Base.

Conclusions: Within The Limitations Of This In-vitro Photoelastic Analysis, The Following Was Concluded : Acetal Partial Denture Frameworks Were Preferred To Use With Implant Supported Removable Partial Denture When Compared With Metal Partial Denture Frameworks, For Preservation Of Bone Around Implant, Acetal Denture Bases Is The Treatment Of Choice.

Mohammed Elsayed Saber, Mohammed Ezzat Elsayed, Sayed Mohammed Elmasry And Moataz Mostafa Bahgat Elmahdy,

ABSTRACT


Purpose: Purpose Of This Study Was To Photoelastic Stress Analysis Of Two Flexible Attachments Implant Supported Mandibular Overdentures With Different Implant Angulations (parallel Implants And Diverged Implants). Using Two Attachment Systems (locator And Sphero-flex)

Materials and Methods: Six Photo Elastic Epoxy Models Were Divided Into Two Groups. For First Group: While Duplication Of The Epoxy Models Two Implants Inserted Vertically (parallel To Each Other) For Second Group: While Duplication Of The Epoxy Models Two Implants Inserted Diverged Distally From Midline With 14 Degree Using Semicircular Protractor. After Epoxy Models Construction,the Locator Attachment Were Placed For The First Group Models While Spheroflex Attachment Were Placed For The Second Group Models. For Both Groups Models, Successive Loads (20,40,60,80,100) Newton Were Applied Using Photo Elastic Stress Analysis Machine By Using Metal Plate Fixed At The Lower First Molar Region Bilaterally Then Stresses Were Recorded And Analyzed. After The First Stage Of Loading, The Implant Attachments For Both Groups Were Interchanged Then The Second Stage Of Loading With Same Successive Loads (20,40,80,100) Were Applied Using The Same Protocol Of The First Stage. The Photo Elastic Stresses For The Two Loading Stages Were Recorded And Statistically Analyzed.

Results: No Statistic Significant Difference Between Two Groups Of Flexible Attachments (locator And Spheroflex) Was Observed When Successive Loads Were Applied On Parallel Implants While There Was Astatic Significant Difference (p? 5%) Between Two Groups When Successive Loads Were Applied On Angulated (diverged) Implants . Conclusion: On Choosing The Flexible Attachment Comparing Locator And Sphero-flex In Case Of Parallel And Diverged Implants Assisted Over Dentures, The Locator Attachment Is More Preferred Regarding Peri Implant Stress Outcome.